I just purchased both the newest 6S leather case and last year's 6 leather case (at a clearance price at Target) and weighed them both.
The 2014 version for the iPhone 6 weighs 15.7 grams and the 2015 version for the 6s weighs more, at 16.9 grams. They are not identical.

The fit is better with the 2015 version on my 6s, the screen lip is higher. Last year's case will go on to my 6s but it takes more force to get it on, and the screen lip along both sides winds up smaller because the phone has grown in thickness.

I saw someone comment that this case will keep your screen from cracking and have to disagree. I just dropped my 6 plus off at the Apple Store for a new $130 screen. My phone fell about 2.5 feet from my bed to my hardwood floor this morning with this case on and the screen is completely shattered. That's not a very far drop and very disappointing. I didn't buy this case for ultra durability, but 2.5 feet.......

Yes. There is a slight lip in the front preventing the screen from shattering on a face down drop. This leather is hard, but it absorbs drops well. For even more protection, see the Apple Silicon Case.